Prof. Dr. Ines Mandić Mulej, Dr. Polonca Štefanič Faculty of Biotechnology, University of Ljubljana It is known that humans behave differently towards relatives than towards those to whom we are not related, that we are more likely to selflessly help a relative. Why? This is explained by the evolutionary theory of kin selection. If we help a relative, we have an indirect benefit, because the relative has most of the same genes as us. We were interested in whether this also applies to bacteria, which also have an incredibly rich social behavior. They are communicative, but they are also aggressive, they are cooperative, but also deceitful. The research “Kind Discrimination of Bacteria” by the lead authors Prof. Dr. Ines Mandić Mulej and Dr. Polonce Štefanič shows that only relatives enter common swarms and that unrelated bacteria remain separate. Kin discrimination also affects the colonization of plant roots. Here again, we observe that related bacteria form a biofilm on the root, where they are in close physical contact; if a plant is inoculated with two unrelated bacteria, only one will grow over most of the root. This shows that there was a struggle for the surface and that one was the winner, while the relatives are quite happy with each other. The original idea for the study was created at the Department of Microbiology, Faculty of Biotechnology, University of Ljubljana, where we also developed recognition tests between bacteria. As a model, we used a very interesting bacterium called Bacillus subtilis, which is important in industry as a producer of various molecules useful to humans, antibiotics, vitamins, enzymes (including those added to washing powders). Researchers from Harvard University (Boston, USA) are also working on the field of kin discrimination, with whom they have established a very fruitful collaboration, also within the framework of the SLO-USA bilateral project. The research also has application implications in the preparation of biofertilizers containing various B. subtilis bacteria. These are known to improve plant growth and protect them from infectious diseases. The discovered kin discrimination in the bacterium B. subtilis, which they are studying, has been used in organic agriculture in China for some time. The group is continuing to research this knowledge, which promises a breakthrough in the future, especially in agriculture, the authors emphasize, who do not lack experience and knowledge. Prof. Ines Mandić-Mulec is an internationally recognized expert in the field of microbial signaling, genetics and ecology of bacteria. As a professor, she conducts research, lectures and leads a dynamic research group, and is also the coordinator of the new field of Agro-Food Microbiology within the Graduate School of Biosciences. Dr. Polonca Štefanič is an established scientist in the field of social interactions and ecology of Bacillus subtilis. As a visiting researcher, she spends a lot of time researching abroad, where she often shares her achievements at international symposia.